The present invention relates to a current sensor for detecting current flowing through a bus bar.
When current flows through a bus bar, such current is detected by a current sensor. In the prior art, a current sensor may be a magnetic sensor that detects the intensity of magnetic fields produced by the current flowing through the bus bar. Such a current sensor includes a core that attracts detectable flux.
To simplify the structure of such a current sensor, it is preferred that the current sensor be free from a core, or be coreless. Japanese Laid-Open Patent Publication Nos. 05-223849 and 08-194016 each propose a coreless structure in which a bus bar is U-shaped to form opposing conductors through which current flows in opposite directions. A magnetic sensor is arranged at an intermediate position between the conductors.
In such a structure, the magnetic fields produced by the current that flows through the opposing conductors (i.e., the current flowing through the bus bar) is amplified at an intermediate position between the conductors. This enables the magnetic sensor to detect current without the use of a core.
However, in such a structure, the magnetic sensor is not fixed to the conductors (bus bar). The magnetic sensor and the conductors are fixed to different members. Thus, the positional relationship between the magnetic sensor and the conductors is not stable. This may result in variations in the values output from the magnetic sensor and thereby lower the detection accuracy of the magnetic sensor. Furthermore, the magnetic sensor and the conductors must be accurately positioned relative to each other in order to ensure accurate detection. Thus, the manufacturing of such a current sensor is burdensome.